DE3331041C2 - - Google Patents

Description

The invention relates to a method according to the preamble of the main claim.

Such a method is known (DE-OS 27 29 113). Here, however, there is a resolution for the text signals suggested that an integer multiple of the resolution of the image material. For far more cases the possibility of reproduction by means of an image signal and Text signal is not. Otherwise the reproduction takes place with the image signal on the one hand and the text signal on the other consecutively.

The invention has for its object a generic To further develop methods so that a simultaneous Recording of the pictures can be done even if the Texts are recorded with a resolution that does not integer multiple of the resolution of a partial image beam corresponds.

This task is carried out in a generic method according to the preamble of the main claim according to the invention solved by its characteristic features.

With the reproduction method according to the invention Image components and drawing components recorded simultaneously using two scanning heads, which are simultaneously shifted in the sub-scanning direction will.

The following is a description of a preferred embodiment the invention in connection with the drawings.

It shows:

Fig. 1 shows an embodiment of the inventive method;

Fig. 2 and Fig. 3 are each a diagram showing the relationship between the scanning beam of an image output head and the scanning beam of a character output head;

FIG. 4 shows an embodiment of a character output head according to the present invention;

FIG. 5 shows an example of a characteristic curve of the piezoelectric element according to FIG. 4;

. Figures 6 and 7 respectively, an alternative embodiment of the character dispensing head.

Fig. 8 shows an example of a dot formation circuit used in the embodiment of Fig. 1;

Fig. 9 shows an example of a circuit interface.

Fig. 1 shows an image reproduction system in conjunction with the inventive method. The system is formed from a section I in which input signals are processed, a section II in which output signals are controlled, and a section III for the output. First, it is explained with reference to Fig. 1, as the input signals of the image data and character data is processed.

Character data from a character input unit 8 are stored in a memory 15 'of a central processing unit (CPU) 15 after conversion into character codes. Then, by naming the desired addresses of the character codes in accordance with a layout previously prepared with the aid of an A / D converter or a coding unit 9 , the font data corresponding to the character codes are retrieved from a font data memory 13 and entered into a character memory 12 .

Character data, for example from tables, maps or rulings, are written into certain cells of the character memory 12 , the addresses for the processing of character data being determined in the same way.

This letter and character data can, if necessary, be changed with the aid of a drawing device 14 for the modification. The device 14 can be provided, for example, in the form of a screen of a Braun tube.

In the meantime, in addition to the process described above, binary data of letters, characters or drawings can be input by scanning using an input scanner 10 .

On the other hand, the image data obtained from an original image with the aid of the input scanner 10 are subjected to color correction, size conversion and the like and are temporarily stored in a storage unit (not shown). After the image data as well as the character or letter data have been given their addresses with the aid of the A / D converter 9 and the graphics output unit 14 in accordance with a layout, the image data are written into the named cells of an image memory 11 .

In the manner described, both the image data and the character or letter data are output to an image output head 1 or a character output head 2 , the feed size of the image output head 1 and the character output head 2 being synchronized in the secondary scanning direction by means of a common feed wheel 17 in accordance with address signals, which are used to control laser beams for the recording of image components and drawing components.

Typically, a suitable picture head and have a suitable drawing head each has its own number of Scanning beams or their own beam diameter on so that the feed size in the sub-scanning direction is not synchronizable. This problem is supposed to can be solved primarily with the present invention.

Fig. 2 shows the general inventive concept, wherein a laser beam B ₁ of the image output head 1 has a diameter of 0.00635 mm (1/4000 inch) and in this case is suitable for emitting ten partial beams at once. A laser beam B ₂ of the character output head 2 (which responds to signals from letter data or character data) has a diameter of 1/1000 inches and in this case is suitable for optionally delivering two or three partial beams at once.

Under the above conditions, the image output head can scan a width of d ₁ = 0.0635 mm (= 1/4000 × 10 = 1/400 inch) at a time, while the character output head 2 can scan a width of d ₁ ′ = 0.508 mm (= 1 / 1000 × 2 = 2/1000 inch) can be scanned if two partial beams are used at the same time or simultaneously. However, the feed size of the two output heads cannot be synchronized here either. However, the image output head 1 can scan a width of d ₂ = 0.127 mm (= 2/400 = 1/200 inches) twice, while the character output head 2 a width of d ₂ ′ = 0.127 mm (= 2/1000 + 3/1000 = 1/200 inch) can be sampled in total if their scanning width d ₂ and d ₂ 'is brought into agreement.

Since the character output head 2 of a five sub-beams corresponding width used in the process described above to complete the scanning firstly two and three sub-beams, where it is assumed that the feed quantity of the character output head 2 coincides with that of the image output head 1, the scanning takes place discontinuously. This error must be corrected. Therefore, according to the invention, a character output head 2 with a beam generator is used which allows scanning with either three or two partial beams ( FIG. 3 (b)) if a scan shown in FIG. 3 (a) is to take place. Provided that, as shown in Fig. 3 (b-1), scanning is carried out with two partial beams, while the character output head 2 is advanced in the sub-scanning direction by a feed amount α (in this embodiment, α = 1/400 inch) , with synchronization with the movement of the image output head after the first scan with two partial beams has taken place, at the beginning of the second scan with three partial beams in the sub-scanning direction - as shown in FIG. 3 (b-2) - a gap β = 0.012 mm ( in this embodiment, β = 1/2000 inch), which corresponds to half the diameter of the partial beam between the position where the head is and the position where the head is to be for the next scan.

According to this embodiment, the character output head 2 described in more detail below is used to correct the gap on the secondary scanning line.

Fig. 4 shows an embodiment of a character output head used in connection with the inventive method. Here, reference numeral 25 denotes a chassis for the character output head 2 synchronously moving with the image dispensing head 1, numeral 26 is a beam forming system that is individually movable to adjust purposes 26, and numeral 28 a kind of piezoelectric material whose characteristic is shown in Fig. 5 , one end of this material or element being attached to one side of the radiation generating system 26 and the other end to the chassis.

The input of a control signal into a high-voltage generator 29 in so-called idle times or suppression times between the first and second scans means that the piezoelectric element 28 changes its shape, so that the beam generation system 26 is shifted a little bit regardless of the feed in the sub-scanning direction and thereby adjusting the gap according to Fig. 3 (b-2).

If the supply of voltage signals to the high-voltage generator 29 is cut off for the third scan, this means that the beam generator 26 is reset to its starting position and is thus ready for the next scan. By repeating the above-described process, another scan can be made so that image components and character components are recorded simultaneously.

A lens for focusing the scanning beam from the radiation generation system 26 on an exposure drum 20 can be movable in accordance with that of the radiation generation system 26 or else stationary if it can cover the displacement distance of the radiation generation system 26 . The method according to the invention can also be used in connection with even more complicated cases.

Assuming that the diameter of the partial beams of the image output head 1 is a ₁, the number of partial beams n ₁, the diameter of the partial beams of the character output head 2 is a ₂ and the number of partial beams n ₂ or n ₃ (n ₃ = n ₂ + 1), with a relation of n ₂ a ₂ < n ₁ a ₁ < n ₂ a ₃, the displacement path can be calculated as follows.

The same calculation can be done for the next scan line. For example, if the feed size for the image output head is 1 ≒ 71.43 µm feed (1/350 l / inch) and for the character output head 2 25 µm feed (1/1000 l / inch) (in this case, the latter applies to each partial beam), so the distance required for the shift is as follows.

1 .: Use of two beams (50 µm), 71.43-50 = 21.43 µm
2 .: Use of three beams (75 µm), 142.86-125 = 17.86 µm
3 .: Use of three beams (75 µm), 214.29-200 = 14.29 µm
4 .: Use of three beams (75 µm), 285.72-275 = 10.72 µm
5 .: Use of three beams (75 µm), 357.15-350 = 7.15 µm
6 .: Use of three beams (75 µm), 428.58-425 = 3.58 µm
7 .: Use of three beams (75 µm), 500-500 = 0 µm

In this case, two sub-beams of the character output head 2 are used the first time and three sub-beams of the character output head 2 are used the second time and the following cycles, and by shifting the beam generator of the character output head 2 by the above distances, the character output head 2 can be used in the sub-scanning direction in accordance with that Image output head 1 are moved.

Fig. 6 shows an alternative embodiment of the character dispensing head 2 can be used instead of the piezoelectric element 28 adjusting screws 30, 31 and a solenoid 32nd

In the embodiment according to FIG. 6, the gap β is corrected in that the position of the radiation generating system 26 is adjusted independently of the chassis 25 with the aid of the solenoid 32 , the adjustment of which is carried out by the screws 30 , 31 .

The method according to the invention can be carried out by using a character output head 2 , which has a two-beam generator 21 a and a three-beam generator 21 b , without an adjustment having to be made. The definition of the axis (l ′ ) of both beam generators 21 a , 21 b , which is shifted in relation to the axis (l) of the chassis by a quarter of the diameter of the scanning beam in the secondary scanning direction (in this case the distance is 1/4000 inches) , means, as shown in Fig. 7 (b), that at the end of the first scan by the two-beam generator 21 a the latter is at the position shown by the broken line in Fig. 7 (a) and that the three -Ray generator 21 b automatically has the correct position without creating a gap or overlapping area on the scanning line. In FIG. 7, L denotes a gap on the main scanning line between the beam generators 21 a and 21 b , the correct or suitable setting of which takes place in accordance with, for example, the number of revolutions of an exposure drum 20 .

As explained above, the image is reproduced with a complete layout of the image components and character components using the output control unit II and the output unit III ( FIG. 1). Units II and III are explained in more detail below.

First, in a coder 19 and in a control circuit 6 for an output scanner, a timing pulse Pa for the control of the image output head 1 and a timing pulse Pb for the control of the character output head 2 are generated. The timing pulse Pa serves as a character for the output of image data D ₁ from an interface 5 to a point formation circuit 4 , the change of the image data D ₁ in a suitable data format for the point formation circuit 4 before storage in a buffer of the interface 5 .

This timing pulse Pa is also input into the dot formation circuit 4 , in which a pattern memory controller or program switch 41 reads a halftone dot pattern signal from a pattern memory 42 in accordance with the timing pulse Pa , this in a comparison circuit 43 with the image data D 1 from the interface 5 compares and outputs a control signal Sb ₁ to turn the scanning beams on or off to the image output head 1 , as shown in Fig. 8.

Methods for producing a halftone image with tone gradation directly from an image signal are described in Japanese Patent Publication No. 52-33523 by the applicant and are therefore not explained in more detail here. The circuit shown in Fig. 8 applies to a scanning beam. A total of ten identical circuits are therefore provided.

On the other hand, the character or letter data output from the character memory 12 to a line buffer 71 of an interface 7 are converted into raster data D 2 in an external switching circuit (not shown) at the command of the CPU 15 , reference being made to the font data stored in the font data memory 13 . Then the data D ₂ are rearranged so that they are suitable for output from the output head, the beam generator emits two or three beams simultaneously. Finally, the rearranged data D ₂ are read out from the line buffer 71 in synchronism with the timing pulse Pb for the characters or letters.

The data D ₂ thus read out from the line latch 71 are then input to a line output switching circuit 72 , in which the line number data is changed in accordance with the number of partial beams to be used for the character output head 2 .

That is, while the character output head 2 changes the number of partial beams to be used (between two and three beams) per revolution of the exposure drum 20 , the number of data lines must be in synchronism with the one revolution pulse Pm (per revolution of the exposure drum 20 ) according to the number of partial beams used can be changed.

The rearranged character or letter data with respect to their number of lines are input as a drive signal Sb ₂ for the scanning beam via a drive amplifier 73 in a drive circuit 3 for the character output.

In this way, an image recording beam B ₁ and a character or letter recording beam B ₂ are issued at the command of the control signals Sb ₁, Sb ₂ from the relevant beam generators at the same time, for recording an image reproduction, in which the image components and book letter components on one Film to be completed.

If, in the embodiment described above, the ruling of the screen or raster has to be changed as required, a corresponding process can easily be carried out with a zoom lens as the image formation lens 17 of the image output head 1 (or with a selected lens, each of which has a specific magnification capacity). be carried out by changing or varying the line of the screen or grid in accordance with the magnification capacity of the lens used. Two methods are available for coordinating the feed size of the character output head and the image output head. According to one of these methods, the number of partial beams of the character output head is changed or varied and the length is set in accordance with the magnification capability of the lens used. According to the other of these methods, a zoom lens is used as the image design lens 18 for the character output head, the magnification of which corresponds to that of the lens of the image output head 1 . If a different number of screen or grid lines is used and the difference is very large, the number of partial beams of the character output head should be increased in advance, while some do not increase with very fine lines (small line or line width) are taken into account.

In the meantime, the process of changing the screen ruling can take place by changing the number of partial beams of the image output head 1 , but this also requires a corresponding change in the number of partial beams of the character output head 2 .

Assuming that the number of partial beams of the image output head 1 is six (with the diameter of each partial beam being 1/4000 inches), the length of the two scans by the image output head corresponds to 1 (6/4000 + 6/4000 = 3/1000 Inch). If, meanwhile, it is assumed that the diameter of each sub-beam of the character output head is 2 (1/1000 inches), the two output heads can be synchronized in the sub-scanning direction by using two sub-beams for the first time and a sub-beam of the character output head for the second time .

In the embodiment described above, the same result can be achieved by optionally using an appropriate number of partial beams of the image output head 1 . However, in order to ensure the uniformity of the halftone dots (for the recording of image components), it is preferable to increase or decrease the number of partial beams of the character output head 2 instead of the number of partial beams of the image output head.

As already explained, the essence of the invention lies in using the feed size of an image output head the feed size of a character or letter output head synchronize in the sub-scanning direction,  so that picture components and characters or letters components recorded practically simultaneously by the number of partial beams of the character output head in the process of image reproduction with an image output head and a character output head, each with its own number of partial beams with their own diameter, each time with a certain number of scan lines will be changed.

The present invention thus becomes a method provided that the simultaneous recording of picture components and drawing or Allows letter components in a simple way, if the screen ruling needs to be changed what has been extremely difficult to accomplish so far.

In brief, the invention relates to a method at which picture signals and sign signals practical can be recorded simultaneously by the output of partial beams from the character output head or an image output head each time at a certain one Number of scan lines increased or decreased is, the feed of both output heads in the Subscanning direction is done synchronously.

Claims (3)

1. A method for image reproduction, wherein signals, namely image signals containing graphic image components on the one hand and text signals containing finer-resolution text components on the other hand are recorded on an exposure drum by means of output heads to form a complete reproduction, characterized in that for the image signals and for the text signals different output heads ( 1 , 2 ) it is provided that the corresponding signals are fed simultaneously, that each output head ( 1 , 2 ) has a radiation generating system ( 26 ) for generating one or more diameters of the same size, but different for different radiation generating systems ( 26 ) contains large sub-beams which are adjacent to one another in the sub-scanning direction, and that the output heads with the sub-beams record the image on the exposure drum ( 20 ) in the main scanning direction and the feed of the two output heads ( 1 , 2 ) in Subscanning direction is done synchronously. 2. The method according to claim 1, characterized in that the number of beam components of at least one output head ( 1 , 2 ) is increased or decreased in accordance with a certain number of scanning lines and that for the radiation generating system ( 26 ) of the output head with a variable number of beam components a setting is carried out in the event that the sub-scanning lengths represented by the product of the diameter of the beam components and the number of beam components of the output heads do not match. 3. The method according to claim 1, characterized in that for both output heads ( 1 , 2 ) a plurality of beam generation systems ( 26 ) are provided, each of which generates a different number of beam components, and that each of these beam generation systems is adjusted in the sub-scanning direction when through the product of the diameter of the beam components and the number of secondary scan lengths represented does not match.